If you’ve just replaced your network switches and tried using any 3rd party SFPs to connect your network backbone, you’ll quickly stumble across an error similar to the following:
Congratulations! The Catalyst switch has just disabled the GBIC port! This happens because Cisco Catalyst switches are configured by default not to work with non-Cisco SFPs.
When a SFP is inserted into a switch’s GBIC port, the switch immediately reads a number of values from the SFP and if it doesn’t like what it sees, it throws the above error message and disables the port.
All SFP modules contain a number of recorded values in their EEPROM and include:
- Vendor Name
- Vendor ID
- Serial Number
- Security Code
- CRC
How To Force Your Cisco Switch to Use 3rd Party SFPs
Despite the error displayed, which leaves no hope for a solution, keep smiling as you’re about to be given one.
There are two undocumented commands which can be used to force the Cisco Catalyst switch to enable the GBIC port and use the 3rd party SFP:
Warning: When Cisco determines that a fault or defect can be traced to the use of third-party transceivers installed by a customer or reseller, then, at Cisco’s discretion, Cisco may withhold support under warranty or a Cisco support program. In the course of providing support for a Cisco networking product Cisco may require that the end user install Cisco transceivers if Cisco determines that removing third-party parts will assist Cisco in diagnosing the cause of a support issue.
3750G-Stack(config)# no errdisable detect cause gbic-invalid
When entering the service unsupported-transceiver command, the switch will automatically throw a warning message as a last hope to prevent the usage of a 3rd party SFP.
The no errdisable detect cause gbic-invalid command will help ensure the GBIC port is not disabled when inserting an invalid GIBC.